JPH1196916A - Manufacture of cathode ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inhibit emission gas from generating in large quantities, and to prevent characteristic deterioration, by dividing all electron guns which are arranged within a vacuum enclosure and have plural necks into plural groups, and sequentially applying thermolysis treatment to cathodes per each group. SOLUTION: First, thermolysis treatment is applied to cathodes of four electron guns constituting the first group A, then the thermolysis treatment is applied to cathodes of another four electron guns constituting the second group B. Thereafter, the thermolysis treatment is sequentially applied to the third, the fourth, the fifth groups C, D, E. The evacuation temperature is kept constant at about 130 degrees. The number of cathodes to be applied with the thermolysis treatment at the same time is decreased, therefore the vacuum within a vacuum enclosure 5 can be prevented from rapidly deteriorating, then the vacuum is not deteriorated to such a degree that the cathodes begin to be poisoned, thus a cathode ray tube having the electron guns with a good emission characteristic can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a cathode ray tube, and more particularly to a method of forming a large image by scanning one phosphor screen by dividing it into a plurality of regions and synthesizing images drawn in each region. The present invention relates to a method for manufacturing a cathode ray tube.

[0002]

2. Description of the Related Art In recent years, there has been a demand for a high-resolution cathode-ray tube for high-definition broadcasting or a large screen associated therewith, and its screen display performance is required to be even more severe. To meet these demands, it is necessary to flatten the screen surface, increase the resolution, and reduce the deflection aberration. At the same time, it is necessary to reduce the weight and thickness of the cathode ray tube.

As a cathode ray tube satisfying such demands,
Japanese Unexamined Patent Publication No. Hei 5-36363 discloses that a phosphor screen having an integral structure formed on the inner surface of a flat face plate is deflected by a plurality of deflectors to deflect electron beams emitted from a plurality of electron guns. A cathode ray tube is shown which is divided into regions and scanned.

According to this cathode ray tube, a flat face plate on which a phosphor screen having an integrated structure is formed;
A vacuum envelope is composed of a flat face plate arranged opposite to the face plate via the side wall, a plurality of funnels joined to the rear plate, and a neck joined to each funnel. An electron gun is sealed in each neck. Each electron gun has at least one cathode for emitting an electron beam.

[0005]

However, there is a problem that it is extremely difficult to manufacture a cathode ray tube having the above configuration. That is, in a normal cathode ray tube, an envelope is formed by one face panel on which a phosphor screen is formed and one funnel having a neck welded to the face panel. The number of the electron guns sealed is one.

In manufacturing such a general cathode ray tube, an envelope is formed by bonding (sealing) a face panel and a funnel with glass. Next, an electron gun is inserted into the neck, and a stem with an exhaust pipe attached to the electron gun is fused (sealed) to the neck. Thereafter, the inside of the envelope is evacuated through the exhaust pipe, and when the exhaust is sufficiently exhausted, the exhaust pipe is fused and closed (chip-off).

In general, in order to generate an electron beam from the cathode of an electron gun, it is necessary to perform a thermal decomposition treatment of the cathode, called lighting, in a vacuum. Specifically, at the time of high vacuum during the evacuation of the envelope, the heater disposed adjacent to the cathode must be energized to heat the cathode and decompose the electron-emitting substance from carbonate to oxide. Thereafter, the exhaust pipe is chipped off, and the cathode is activated in the aging step, whereby the electron beam can be extracted.

[0008] Usually, at the cathode called an oxide cathode, (Ba, Sr, Ca) CO ₃ → (Ba, Sr, Ca)
The reaction manifests as CO + CO ₂ . At this time, as is clear from the above equation, carbon dioxide gas is generated by thermal decomposition of the cathode.

Normally, the amount of carbon dioxide gas generated is very small compared to the capacity of the cathode ray tube, so that there is no problem due to getter adsorption or the like after exhaust. Further, since the lighting is performed during the exhaust, the carbon dioxide gas is sufficiently exhausted to the outside of the tube by the exhaust, so that there is no problem.

On the other hand, one face panel having an integrated phosphor screen, a plurality of necks,
In the above-mentioned cathode ray tube having a plurality of electron guns, several times the number of cathodes is arranged in the tube in comparison with a normal cathode ray tube. Therefore, when all the cathodes are lit at the same time as in a normal cathode ray tube, the amount of gas emitted from the cathode reaches several times that of a normal cathode ray tube, and is a non-negligible amount.

That is, according to experiments conducted by the present inventors, it has been found that when a large amount of released gas is generated in a cathode ray tube which has been in a high vacuum state during the evacuation process, the degree of vacuum is greatly reduced. For example, the released gas reduces the degree of vacuum of the cathode ray tube from 1 × 10 ⁻⁷ to 1 × 10 ⁻⁵ Torr. Such a decrease in the degree of vacuum causes the following problem.

First, when the degree of vacuum in the cathode ray tube decreases,
The cathode itself is poisoned by the gas emitted from the cathode,
Eventually, it becomes impossible to obtain sufficient electron emission as a cathode ray tube. This results in deterioration of the emission life characteristics of the electron gun, which is a fatal defect such that good emission cannot be maintained as a cathode ray tube or an electron beam is not emitted. Even if the getter is flushed after the exhaust pipe is chipped off and the released gas is adsorbed, the degree of vacuum of the cathode ray tube cannot be sufficiently increased in some cases.

A sudden change in the degree of vacuum has an excessive effect on a vacuum pump used for exhausting a cathode ray tube, and may cause a failure of the exhaust device itself. In addition, since the gas generated during lighting is generated in a short time (several seconds to several minutes), the atmospheric pressure acting on the cathode ray tube changes rapidly due to rapid gas release, and the envelope cannot withstand during the manufacturing process. The cathode ray tube may implode.

As described above, the generation of a large amount of released gas poses a serious problem in the production of a cathode ray tube in terms of characteristic deterioration, cost, safety, and the like. The present invention has been made in view of the above points, and an object of the present invention is to solve the above-mentioned problems. A phosphor screen provided on a face panel is arranged in a plurality of necks. It is an object of the present invention to provide a manufacturing method capable of manufacturing a cathode ray tube that scans in a plurality of regions by electron beams emitted from a plurality of electron guns, which is safe and without deterioration in emission characteristics.

[0015]

In order to achieve the above object, a method of manufacturing a cathode ray tube according to the present invention comprises a substantially rectangular face plate having a substantially flat face and a face plate substantially parallel to the face plate. A rear plate, a phosphor screen formed on the inner surface of the face plate,
A plurality of funnels provided on the rear plate, and a vacuum envelope having a plurality of necks respectively joined to the funnel, and disposed between the face plate and the rear plate; A plate support member for supporting an acting atmospheric pressure load, and a plurality of electron guns respectively provided in the plurality of necks and irradiating an electron beam for each divided screen to the divided screen obtained by dividing the phosphor screen into a plurality. In the method for manufacturing a cathode ray tube having, the electron gun is disposed in each of the plurality of necks,
When heating and decomposing the cathode of the electron gun while exhausting the inside of the vacuum envelope, all the electron guns disposed in the vacuum envelope are divided into a plurality of groups, and each group is sequentially divided into groups. And a heat decomposition treatment.

As described above, when all the electron guns disposed in the vacuum envelope are divided into a plurality of groups and the thermal decomposition process is sequentially performed for each cathode of the electron guns in each group, the vacuum envelope is A large amount of cathode discharge gas is not generated in the chamber at a time, and a rapid decrease in the degree of vacuum of the vacuum envelope can be suppressed. This makes it possible to prevent poisoning of the cathode, damage to the exhaust device, implosion of the vacuum envelope, and the like.

The divided regions of the phosphor screen are arranged vertically and horizontally, and when performing the thermal decomposition process of the cathode, the divided regions of the electron guns corresponding to the divided regions of one row or one column are subjected to thermal decomposition. Perform processing.

According to the present invention, the electron guns included in each group are constituted by electron guns corresponding to a plurality of divided regions symmetrically arranged with respect to the center of the phosphor screen. Features.

As described above, a plurality of groups are formed by the electron guns corresponding to the plurality of divided areas symmetrically arranged with respect to the center of the phosphor screen, and these groups are sequentially subjected to thermal decomposition processing, whereby Can be processed under the same conditions, and the emission characteristics of the cathodes in each group become substantially the same. Therefore, the emission characteristics, that is, the luminance characteristics become uniform at the positions where the phosphor screen is symmetrical.

According to the manufacturing method of the present invention, the thermal decomposition process is performed in order from the group including the electron gun corresponding to the divided region far from the center of the phosphor screen among the plurality of groups. .

Further, according to the manufacturing method of the present invention, when performing the thermal decomposition process by dividing into a plurality of groups, the number of the electron guns included in the group to be subjected to the thermal decomposition process is first increased by the number of the heat guns. It is characterized in that the number of electron guns included in the group for performing the disassembling process is the same or less.

According to the above-described manufacturing method, first, a thermal decomposition process is performed from a group including an electron gun corresponding to a divided region (for example, a corner portion) located at a peripheral portion of a phosphor screen, and then, a thermal decomposition process is performed. The thermal decomposition process is performed on the cathodes of the group located inside, that is, on the center side of the phosphor screen. In this way, the thermal decomposition processing is sequentially performed, and finally, the thermal decomposition processing of the group including the electron gun corresponding to the divided region located at the center of the phosphor screen is performed.

In this case, it is possible to minimize the poisoning of the cathode of the electron gun corresponding to the divided area located at the center of the phosphor screen, and to minimize the portion of the entire divided area where the cathode life is required most. Can be prevented from being deteriorated.

For example, if the number of cathodes included in the first group for performing the thermal decomposition treatment is nl, and the number of cathodes included in the group for starting the next thermal decomposition treatment is n2, then nl ≧ Group as n2. When the order of the groups to be thermally decomposed and the number of cathodes included in each group are determined in such a relationship, the thermal decomposition is performed first due to deterioration of the degree of vacuum due to the thermal decomposition of the group to be performed later. It is possible to reduce the adverse effects on the cathodes of the other groups, and to manufacture a cathode ray tube having good emission characteristics.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a cathode ray tube according to an embodiment of the present invention will be described in detail with reference to the drawings. As shown in FIGS. 1 and 2, the cathode ray tube includes a vacuum envelope 5, which is joined to a substantially rectangular flat face plate 1 and a peripheral portion of the face plate 1. And a frame-shaped side wall 2 extending substantially perpendicular to the face plate 1, and a substantially rectangular flat rear plate 3 joined to the side wall 2 and arranged in parallel with the face plate 1. , A plurality of funnels 4 joined to the rear plate 3. A neck 6 is joined to each funnel 4.

The rear plate 3 has a plurality of, for example, 2
Zero rectangular openings 9 are formed and arranged in a matrix, for example, arranged in five horizontal rows and four vertical columns. Each of the plurality of funnels 4 has a corresponding opening 9.
, And five in the horizontal direction (X direction) and four in the vertical direction (Y direction).
There are zero.

On the inner surface of the face plate 1, blue, green,
An integrated phosphor screen 8 having a stripe-shaped three-color phosphor layer extending in the vertical direction that emits red light and a black stripe (light shielding layer) provided between the three-color phosphor layers is formed. ing. Further, a flat shadow mask 7 is arranged inside the vacuum envelope 5 so as to face the phosphor screen 8. A number of electron beam passage holes are formed in the shadow mask 7.

Between the face plate 1 and the rear plate 3, there is disposed a support member 12 composed of a plurality of metal columns for supporting the atmospheric load applied to the face plate 1 and the rear plate 3.

An electron gun 14 for emitting an electron beam toward the phosphor screen 8 is provided in each of the necks 6 provided on the plurality of funnels 4, and a total of 20 electron guns are provided in the vacuum envelope 5. Electron guns are arranged. In addition, each neck 6
A deflecting device 16 is mounted on the outside.

As shown in FIG. 3, each electron gun 14 emits three electron beams, and has three cathodes 2.
0, a heater 22 disposed adjacent to each cathode,
And a plurality of electronic lenses 24 and the like.
Therefore, a total of 60 cathodes 2 are provided in the vacuum envelope 5.
0 is provided.

The electron beam emitted from the electron gun 14 is
The screen is deflected in the horizontal and vertical directions by a magnetic field generated by the deflecting device 16, and the phosphor screen 8 is divided into a plurality of areas, five in the illustrated example,
Scanning is performed by dividing the image into four regions R1 to R20 in total in the vertical direction. An image drawn on the phosphor screen 8 by the divided scanning is transmitted to the electron gun 14 or the deflecting device 1.
6 are connected by a signal applied to the phosphor screen 8.
One large image is reproduced without interruption over the entire surface of the image.

Next, a method of manufacturing the cathode ray tube configured as described above will be described. First, with the support member 12 and the shadow mask 7 set, the electron gun 1 is placed in the face plate 1, the side wall 2, the rear plate 3, and the neck 6.
After forming the envelope 5 by joining the funnels 4 on which the funnels 4 are arranged with frit glass, the interior of the envelope 5 is exhausted.
As shown in FIG. 2, in the evacuation step, an evacuation pipe 26 and a vacuum pump 28 are connected to the side wall 2 of the envelope 5. By driving the vacuum pump 28 in this state, the envelope 5
Exhaust the inside. During the evacuation process, the evacuation is performed while heating the entire envelope in order to efficiently release the gas in the envelope 5 in a short time.

At this time, when the degree of vacuum in the envelope 5 has decreased to some extent, the heater 21 of the electron gun 14 is energized to thermally decompose the cathode 20. The current applied to the heater 21 starts from a current amount smaller than the current flowing when the cathode ray tube is used in general, and the current amount is sequentially increased. Then, finally, a current that is slightly larger than the current that normally uses a cathode ray tube is applied to the heater 21 to perform the thermal decomposition process.

In an experiment conducted by the inventors, when the cathodes of all the electron guns 14 disposed in the envelope 5 were simultaneously subjected to thermal decomposition treatment, the degree of vacuum in the envelope was reduced by the gas released from the cathode. Degrades rapidly. For example, the degree of vacuum is 1 × 10
^It rapidly deteriorates from ^-6 Torr to about 1 × 10 ^-4 Torr. This degree of vacuum is a deterioration of the degree of vacuum sufficient to poison the cathode 21 with the gas. Generally, the envelope 5
Gas inner differ in vacuum to poison the cathode by the type, in the case of CO _2, about 1 × 10 ^-4 is known to be a vacuum degree of poisoning start.

Therefore, according to the present embodiment, the envelope 5
The plurality of electron guns 14 disposed in the plurality of groups are divided into a plurality of groups, for example, 20 divided regions R of the phosphor screen 8.
First to fifth five groups A, B, C, with four electron guns corresponding to one row of 1 to R20 as one group.
It is divided into D and E, and the thermal decomposition treatment is sequentially performed for each group.

As shown in FIG. 4, first, the first group A
The cathodes 21 of the four electron guns 14 constituting the second group B are subjected to thermal decomposition processing, and after the completion of the thermal decomposition processing, the cathodes 21 of the other four electron guns constituting the second group B are subjected to thermal decomposition processing. Thereafter, the third, fourth, and fifth groups C, D, and E are sequentially subjected to thermal decomposition processing.

At this time, the exhaust gas temperature is about 130 ° C., and from the time when the thermal decomposition treatment of the first group A is started,
The temperature of the exhaust gas is set to a constant value until the thermal decomposition treatment of the last fifth group E is completed.

After the thermal decomposition processing of all the groups is completed, the exhaust pipe 26 is chipped off, and the deflection yoke 16 is attached to each neck 6, whereby a cathode ray tube is manufactured.

FIG. 4 shows a change in the degree of vacuum in the envelope 5 when the above-described thermal decomposition treatment is performed. As can be seen from this figure, by grouping all the electron guns 14 in rows and sequentially performing the thermal decomposition process for each cathode 20 in each group, the number of cathodes to be thermally decomposed at one time is reduced, and the envelope is reduced. 5 can be prevented from abrupt deterioration of the degree of vacuum. Therefore, the degree of vacuum in the envelope 5 does not deteriorate to a degree at which poisoning of the cathode 20 starts, and a cathode ray tube having an electron gun with good emission characteristics can be obtained.

Further, by preventing a rapid deterioration of the degree of vacuum in the envelope 5, the load on the vacuum pump 28 can be reduced, and a sudden change in the atmospheric pressure with respect to the envelope can be suppressed. The damage of the envelope can be prevented.

Further, the exhaust gas temperature at the time of the cathode pyrolysis treatment is changed from when the first group A pyrolysis treatment is started.
Since the temperature is set to be constant until the end of the thermal decomposition treatment of the fifth group E, the apparent change in the degree of vacuum due to the fluctuation of the exhaust gas temperature can be ignored, and the thermal decomposition treatment of each group can be performed. It can be performed under almost the same conditions. Therefore, finally, the emission characteristics can be made uniform over the entire area of the phosphor screen 8.

In the above-described embodiment, the number of electron guns to be divided into groups can be appropriately selected according to the internal capacity of the envelope 5 and the exhaust capacity of the vacuum pump 28. In addition, if the degree of vacuum in the envelope 5 can be suppressed to a value equal to or lower than the degree of vacuum at which cathode poisoning starts, it is not necessary to wait for the end of the thermal decomposition processing of the group that has been performed earlier. By adjusting the temperature so that the peak of the amount of gas released during the thermal decomposition treatment of each group does not coincide with time, it is possible to perform the thermal decomposition treatment of the cathode if the degree of vacuum below the cathode poisoning start is maintained. it can.

In the above embodiment, the electron guns are divided into groups to perform the heat decomposition process, but the electron guns in each row may be grouped to perform the heat decomposition process of the cathode. .

Next, a method of manufacturing a cathode ray tube according to a second embodiment of the present invention will be described. According to the second embodiment, when the plurality of electron guns 14 are divided into a plurality of groups and the cathode thermal decomposition process is sequentially performed for each group, each group is symmetrical with respect to the center of the phosphor screen 8. , And an electron gun corresponding to the plurality of divided regions.

According to the second embodiment, the number of the electron guns included in the group to be subjected to the thermal decomposition processing is increased by the number of the electron guns included in the group to be subjected to the thermal decomposition processing. The guns are grouped so that they have fewer or the same number of guns. That is, when the number of cathodes included in the first group that performs the thermal decomposition process is nl, and the number of cathodes included in the group that next starts the thermal decomposition process is n2, the electron gun 14 is nl Grouping is performed so that ≧ n2.

For example, as shown in FIG. 5, of the 20 divided areas R1 to R20 of the phosphor screen 8, the divided areas R1, 5, 6, 10, 11, 1 and 5 in the first and fifth rows are provided.
The eight electron guns 14 respectively corresponding to 5, 16, and 20 are divided into the first group A, the first row excluding the four corners, and the fourth row.
Six electron guns 14 corresponding to the divided areas R2, 3, 4, 17, 18, and 19 in the row correspond to the second group B and the remaining divided areas R7, 8, 9, 12, 13, and 14, respectively. The six electron guns are divided into three groups, a third group C.

Then, from the group including the electron guns corresponding to the divided areas located at the periphery of the phosphor screen 8,
The cathode is thermally decomposed in order to the group including the electron gun corresponding to the divided region located at the center of the phosphor screen. That is, in the present embodiment, the first,
The cathode thermal decomposition treatment of each group is performed in the order of the second and third groups.

The other steps and other conditions in the manufacturing method are the same as those in the first embodiment, and a detailed description thereof will be omitted. FIG. 6 shows a change in the degree of vacuum in the envelope 5 when the above-described thermal decomposition treatment is performed.
As can be seen from this figure, by dividing all the electron guns 14 into a plurality of groups and sequentially performing the thermal decomposition process for each of the cathodes 20 of each group, the number of cathodes to be thermally decomposed at once decreases, and the envelope is reduced. 5 can be prevented from abrupt deterioration of the degree of vacuum. Therefore, also in the second embodiment, the same operation and effect as in the first embodiment can be obtained.

Further, according to the second embodiment, the electron guns of each group are constituted by a plurality of electron guns symmetrically arranged with respect to the center of the phosphor screen, so that the same group can have the same number of electron guns. The divided region corresponding to the cathode thermally decomposed under the condition is positioned to cope with the center of the phosphor screen, and the difference in brightness between these coping portions can be reduced.

According to the second embodiment, the thermal decomposition process is performed in order from the group including the electron gun 14 corresponding to the divided region far from the center of the phosphor screen 8 among the plurality of groups. The divided area corresponding to the cathode to be thermally decomposed later is near the center of the phosphor screen which is most noticed by humans. Therefore, it is possible to minimize the poisoning of the cathode corresponding to the divided region at the center of the phosphor screen.

That is, when the cathode corresponding to the divided region at the peripheral portion of the phosphor screen is subjected to the thermal decomposition before the cathode corresponding to the divided region at the center of the phosphor screen is subjected to the thermal decomposition, the cathode is emitted due to the dispersion of the cathode. Even if the amount of the gas exceeds the predetermined amount and the possibility of cathode poisoning occurs, the next group of thermal decomposition treatment can be performed after the degree of vacuum is improved. Therefore, since the thermal decomposition treatment of the cathode corresponding to the divided region at the center of the phosphor screen is finally performed under favorable conditions, it is possible to minimize the poisoning of these cathodes. As a result, the emission life at the center of the phosphor screen, which attracts the most attention, can be kept good.

Further, according to the second embodiment, the number of the electron guns included in the group to be subjected to the thermal decomposition processing first is increased by the number of the electron guns included in the group to be subjected to the subsequent thermal decomposition processing. The guns are grouped so that they have fewer or the same number of guns. Therefore, FIG.
As is clear from the above, the degree of vacuum deterioration during the subsequent thermal decomposition treatment is naturally reduced, and the degree of poisoning of the previously thermally decomposed cathode during the subsequent thermal decomposition treatment of the other cathode is sufficiently reduced. It becomes possible.

In the second embodiment, each group only needs to be composed of electron guns symmetrically arranged with respect to the center of the phosphor screen.
If it is configured to satisfy the relationship of l ≧ n2, it can be freely selected. For example, as shown in FIG. 7, of the 20 divided regions R1 to R20 of the phosphor screen 8, the divided regions R1, 5, 6, 10, 1 in the first and fifth columns are provided.
Eight electron guns 14 corresponding to 1, 15, 16 and 20, respectively, are assigned to the first group A, the second example and the fifth row of divided regions R2, 4, 7, 9, 12, 14, 17 and 19, respectively. The corresponding six electron guns 14 are divided into three groups of a second group B, and the six electron guns respectively corresponding to the divided regions R3, 8, 13, and 18 in the third column are referred to as a third group C. Is also good.

The method for manufacturing a cathode ray tube according to the present invention comprises:
The present invention can be applied to a cathode ray tube using either an oxide electrode or an impregnated electrode as a cathode. Further, the manufacturing method of the present invention provides a cathode ray tube having no shadow mask,
The present invention is also applicable to other cathode ray tubes having different numbers of phosphor screen divisions. Further, the present invention is applicable to a cathode ray tube having a different number of cathodes of an electron gun. Further, in the above-described embodiment, the exhaust temperature during the thermal decomposition treatment is set to 130 degrees, but may be set to a different exhaust temperature as needed.

[0055]

As described above in detail, according to the present invention, a plurality of electron beams emitted from a plurality of electron guns disposed in a plurality of necks cause a plurality of phosphor screens provided on a face panel to be irradiated by a plurality of electron beams. It is possible to provide a manufacturing method capable of manufacturing a cathode ray tube that scans in different regions safely and at a low cost without deteriorating emission characteristics.

[0056]

[Brief description of the drawings]

[0057]

FIG. 1 is a perspective view showing an example of a cathode ray tube to which a manufacturing method according to an embodiment of the present invention is applied.

[0058]

FIG. 2 is a side view showing the cathode ray tube partially broken away.

[0059]

FIG. 3 is a view schematically showing an electron gun of the cathode ray tube.

[0060]

FIG. 4 is a graph showing a change in the degree of vacuum during a cathodic pyrolysis treatment in the cathode ray tube manufacturing process.

[0061]

FIG. 5 is a plan view of a phosphor screen for explaining grouping of electron guns in a manufacturing method according to a second embodiment of the present invention.

[0062]

FIG. 6 is a graph showing a change in the degree of vacuum during a cathode thermal decomposition process in the second embodiment.

[0063]

FIG. 7 is a plan view of a phosphor screen for explaining another grouping of electron guns in the manufacturing method according to the second embodiment.

[0064]

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Face panel 3 ... Rear panel 4 ... Funnel 5 ... Vacuum envelope 6 ... Neck 7 ... Shadow mask 8 ... Phosphor screen 12 ... Plate support member 14 ... Electron gun 20 ... Cathode R1-R20 ... Division area A ... 1st Group B: Second group C: Third group D: Fourth group

Claims (9)

[Claims] 1. A substantially rectangular face plate having a substantially flat shape, a rear plate disposed substantially parallel to and facing the face plate, a phosphor screen formed on an inner surface of the face plate, and provided on the rear plate. A plurality of funnels, and a vacuum envelope having a plurality of necks respectively joined to the funnel, and disposed between the face plate and the rear plate to apply an atmospheric pressure load acting on the vacuum envelope. A cathode ray tube comprising: a supporting plate supporting member; and a plurality of electron guns respectively provided in the plurality of necks and irradiating an electron beam for each of the divided screens obtained by dividing the phosphor screen into a plurality of divided screens. In the manufacturing method, the electron gun is arranged in each of the plurality of necks, and the electron gun is evacuated while evacuating the vacuum envelope. When performing the thermal decomposition treatment of the cathode of, all the electron guns disposed in the vacuum envelope are divided into a plurality of groups, and for each group,
A method for producing a cathode ray tube, comprising performing a thermal decomposition treatment. 2. The divided regions of the phosphor screen are arranged vertically and horizontally, and the electron guns included in each group are constituted by electron guns corresponding to one line of the divided regions. The method for manufacturing a cathode ray tube according to claim 1, wherein: 3. The divided areas of the phosphor screen are arranged vertically and horizontally, and the electron guns included in each group are constituted by electron guns corresponding to one row of the divided areas. The method for manufacturing a cathode ray tube according to claim 1, wherein: 4. An electron gun included in each of said groups is constituted by an electron gun corresponding to a plurality of divided regions symmetrically arranged with respect to a center of said phosphor screen. 2. The method for manufacturing a cathode ray tube according to 1. 5. The cathode ray according to claim 1, wherein the thermal decomposition process is performed sequentially from a group including an electron gun corresponding to a divided region far from the center of the phosphor screen among the plurality of groups. Pipe manufacturing method. 6. The method according to claim 1, wherein the number of electron guns included in the group to be subjected to the subsequent thermal decomposition is equal to or smaller than the number of electron guns included in the group to be subjected to the thermal decomposition first. 6. The method for producing a cathode ray tube according to any one of items 5 to 5. 7. A method according to claim 1, wherein the plurality of groups are sequentially subjected to the thermal decomposition so that the peaks of the amount of gas released from the cathode by the thermal decomposition of each group are temporally shifted from each other. A method for producing a cathode ray tube according to any one of the preceding claims. 8. The method for manufacturing a cathode ray tube according to claim 1, wherein after the thermal decomposition process of one group is completed, the thermal decomposition process of the next group is performed. 9. The vacuum envelope is evacuated so that exhaust temperatures at the start and end of the thermal decomposition treatment of each group are substantially the same. 2. The method for producing a cathode ray tube according to claim 1.